The present invention comprises a new and distinct cultivar of calla lily, botanically known as Zantedeschia sprengeri and hereinafter referred to by the cultivar name ‘Vermont’.
‘Vermont’ is a product of a planned breeding program, which had the objective of creating Zantedeschia hybrids for pot flower production in a wide range of colors with a large, classic flower shape. The breeding program began in 1989, and the new cultivar is a seedling selected from the crossing of a Zantedeschia sprengeri selection referred to as ‘Garnet Glow’ (female parent, unpatented) with a Zantedeschia sprengeri selection referred to as ‘Allure’ (male parent, unpatented). ‘Vermont’ was selected in 2010 by the inventor in 't Zand, The Netherlands as one flowering plant within the progeny of the stated cross.
The first act of asexual reproduction of ‘Vermont’ by tissue culture was performed by the inventor in September of 2010 in 't Zand, The Netherlands. Subsequent asexual reproductions by tissue culture at the same location have demonstrated that the combination of characteristics as herein disclosed for the new cultivar are retained and reproduced true to type through successive generations of asexual reproduction.
The following observations, measurements and comparisons describe plants grown in 14 cm pots in 't Zand, The Netherlands under greenhouse conditions, which approximate those generally used in horticultural practice. Color references are made to the R.H.S. Colour Chart of The Royal Horticultural Society of London, except where general color terms of ordinary significance are used.
The present invention has not been evaluated under all possible environmental conditions. The phenotype may vary with variations in environment without a change in the genotype of the plant.
The following traits have been repeatedly observed and determined to be basic characteristics of ‘Vermont’ which, in combination, distinguish this calla lily as a new and distinct cultivar:                1. Purple-colored spathe;        2. Natural dwarf plant architecture; and        3. High inflorescence production.        
Further, when compared to calla lily plant named ‘Black Star’ (U.S. Plant Pat. No. 14,844), ‘Black Star’ has an upper and lower surface spathe color that varies between Greyed-Purple Group RHS 187A and Black Group RHS 202A, whereas the upper surface spathe color of ‘Vermont’ varies between Red-Purple Group RHS 60A and 60B and the lower surface spathe color of ‘Vermont’ varies between Green Group RHS 143B and 143C.
Table 1 provides similarities and differences of ‘Vermont’ to its parents, Zantedeschia sprengeri selections ‘Garnet Glow’ and ‘Allure’.
TABLE 1‘Vermont’SimilaritiesDifferences‘Garnet Glow’Number of inflorescencesSpathe colorLeaf shapeWhite leaf spotsSpathe shape‘Allure’Leaf shapeSpathe colorSpathe shapeNumber of inflorescences